Thermostatic control for gas burners



June 30, 1959 R. F. wlBERG ETAL Tmamosmnc` CONTROL FOR GAS BURNERS Filed July 10, 1957 /A/L/f-A/To/zs @A YMoNo E w/ef/zq A/vo FRANK d. s/LHAVY m ww Arrow/EVS.

(the uppermost position of the capsule. -also provided with inwardly bent tongues below the :zcapsule to limit the downward movement of the capsule United States Patent O Mce THERMOSTATIC CONTROL FOR GAS BURNERS Raymond F. Wiberg and Frank J. Silhavy, Park Forest, Ill., assignors to Harper-Wyman Company, Chicago, Ill., a corporation of Illinois Application July 10, 1957, Serial No. 671,047

14 claims. (c1. '1s-36s) The present invention relates to thermostatic controls and particularly to thermostatic controls for burners of the type including a central generally tubular opening. More specically, the invention is directed to thermal responsive means, which may be called a sensing element or unit, and which is adapted to engage and to be responsive to the temperature of a cooking vessel heated by the burner.

An object of the present invention is to provide a new and improved thermostatic sensing unit for controlling a gas valve to regulate the flow of gas to a burner in response to the temperature of a cooking vessel heated by the burner.

A further object of the present invention is to provide a new and` improved mounting or supporting structure for a thermostatic capsule and adapted to maintain the capsule in engagement with the bottom of the cooking vessel and to shield it from extraneous heat and also to provide a device of this character which is better cooled by a greater upow of air around it.

A further object of the present invention is to provide a thermostatic sensing unit of the type described above which can be constructed and assembled readily and economically.

lIn brief, the thermostatic control of the present invention is of a type adapted to be supported below a burner and to extend upwardly in the central opening of a conventional burner for engagement with the bottom of the cooking vessel supported as upon a grate located above the burner. In accordance with one feature of the invention, the thermostatic means or sensing unit includes shielding means which is constructed to include a generally conical portion extendingdownwardly and inwardly thereby to provide a greater upiiow of air around the sensing element to cool it to decrease `the adverse effect of ambient temperature changes upon the sensing unit. The sensing unit in- ,cludes a capsule biased resiliently upward as by a helical capillary tube mounted upon a reducer coupling element located below it. The reducer has connected to it also an enlarged capillary tube leading to a combined gas 4shuto and temperature selecting valve including thermostatic actuating means controlled in response to variations in the volume of thermostatic fluid. The

The capillary tube above the reducer is shielded by vthe generally conical shield which is biased upwardly by spring means disposed slidably below the conical shield. The spring is surrounded by an inverted spring covering cup. 'Ihe upper end of the shield is closed by a rim detachably secured to the shield and including a portion projecting inwardly to prevent or to determine The shield is relative to the shield. The shield, post and base are 2,892,349 Patented June V30,

provided with axial slots in order to facilitate mounting thereof relative to an assembly including the reducer element and the capillary tubes extending in opposite directions from the element. i

Other objects and advantages of the present invention will become apparent from the ensuing description of an illustrative embodiment of the invention, in the course of which reference is had to the accompanying drawings, in which:

Fig. 1 is a side elevational view, partly in phantom, illustrating the thermostatic control means of the present invention in combination with a thermostatic gas valve,`

Fig. 2 is a perspective view of the sensing unit;

Fig. 3 is an enlarged axial vertical cross sectional view through the sensing unit; and Y Fig. 4 is a horizontal cross sectionalrview taken along the line 4 4 of Fig. 3.

Referring now to the drawings and iirst to Eig; l, the thermostatic control of the present invention is' indicated as a Whole by the reference character 10. The major components shown in this view are a thermostatic uid containing capsule 12, a shield 14 comprising a lower generally inverted and truncated conical portion 16 and an upper rim 18, a spring retaining cup 20 and a tubular mounting post 22. This thermostatic control, hereinafter referred to as a sensing unit, is connected by an elongated capillary tube 24 to a combined gas shutoff and temperature adjusting valve, indicated as a whole by reference character 26. This valve forms no part of the present invention, it being disclosed and claimed in the contemporaneously iiled application of Charles C. Lamar, Raymond F. Wiberg and FrankJ. Silhavy, application Serial No. 671,048, tiled July 10, 1957, and assigned to the assignee of this application.

Before describing in detail the sensing 'unit of the present invention, the valve 26 will be described briey. The valve is mounted upon Va gas supply manifold 30 by means of a mounting plate 32. It includes arvalve body 34, which may be made as a forging or casting and within which is mounted a rotatable valve plug, not shown, an intermediate tubular housing portion V36 within which is mounted a gas flow regulating valve, and associated thermostatic actuating means such as a diaphragm assembly, also not shown, and an end cap 38. The capillary tube 24 terminates in a fitting 40 secured as by a lock nut 41 to the end cap to which the diaphragm assembly is also secured.

The valve is operable by a handle 42 disposed in front of a panel 44 of the range. By turning the valve handle 42 the valve plug is turned from an off position to an on position. At the same time, the turning of the valve results in adjustment of the temperature to be maintained by the thermostatically actuated valve under the control of the sensing unit. For additional details and'description of operation of the valve, reference may be had to the above-referred to copending application.

The thermostatic sensing unit is shown in cooperative relation to a gas burner 50 having peripheral outlet ports 51 and a generally cylindrical opening 52 into which the sensing unit extends so that it extends somewhat above the top of the burner in the absence of a cooking vessel. The burner may be of conventional construction and has been illustrated but diagrammatically. It includes an inlet passageway 54 coupled by means of a conventional mixing or venturi tube 56 to an outlet hood or nozzle 58 forming part of the gas valve 26 and mounted upon a nipple or tting 59. Y

A cooking vessel 60, shown but fragmentarily, is adapted to be seated above the burnerr 50 as upon a grate 61 disposed above the burner and which may be of con- Ventional construction and onlyY the grate bars' of which have been illustrated. When so seated, it engages both the thermostatic capsule 12 and the rim 18 of the shield, both of which are biased resiliently upward into engagement with the bottom of the vessel, whereby the capsule is effectively responsive to the temperature of the vessel and shielded from a burner and other ambient temperature variations by the shield 14.

Referring now more particularly to Figs. 2, 3 and 4, it may be noted that the generally tubular mounting post 22 is mounted upon and xedly secured to suitable supporting structure which may take the form of a supporting plate 66 adapted suitably to be secured to structure on the gas range, not shown. The base plate 66 is centrally apertured and provided with an upstanding annular flange 68 'whereby it is adapted effectively to be secured to the post as by a welding operation. The post may be of a height suited 'for a particular installation. The base plate is provided with oppositely disposed end slots 70 for reception of suitable securing means, not shown. Also, for assembly purposes and as will be described in greater detail hereinafter, both the base plate and post are slotted as indicated by the reference characters 72 and 74, respectively.

The capillary tube 24 is secured as by brazing to the lower end of a reducer coupling element indicated as a whole by the reference character 76 and mounted at the upper end of post 22. The post and coupling element are secured in assembled'relation by indenting tongues 80 formed at the upper end of the post into an annular groove 82 formed in the lower reduced diameter portion 84 ofthe coupling element, the groove being so located that the upper enlarged portion or head 86 of the coupling element sits upon the upper end of the post 22.

A somewhat smaller capillary tube 88 is secured to the upper end of the reducer coupling element, it being in fluid communication with the lower coupling tube through an axial passageway 90 in the coupling element as clearly indicated in Fig. 3.

The thermostatic capsule 12 may be constructed in conventional manner. As illustrated, it includes an upper 'plate 92 of inverted cup-shape and having an outwardly Aextending annular ange 94 adapted to be engaged with an inwardly extending annular flange 96 formed on the shield rim 18, the engagement of these two parts determining the uppermost position of the capsule. The capsule includes also a lower cup-shaped element 98 spaced from the plate 92 to provide a thermostatic fluid receiving chamber 100. Thermostatic fluid is supplied to the system through a filler tube 102.

The upper capillary tube 88 is connected as by brazing to the capsule 12 and so as to be in uid communication with the chamber 100. The tube 88 is provided with an intermediate helical portion 106 providing a resilient means .for spring biasing the capsule 12 upwardly .so that when a cooking vessel is placed upon the apparatus the helical portion 106 resiliently'forces the capsule 12against -the bottom of a vessel.

The thermostatic shield 14 includes the lower and upper portions 16 and 18 referred to previously. The portion 16 includes an upper generally cylindrical portion 110 to which the rim 18 is detachably coupled by means of tongues 112 bent inwardly from the lower portion of the rim 18 and extending into openings formed by the inwardly bent tongues 114 in the upper portion 110 of the shield element 16. These tongues 114 limit the downward movement of the capsule relative to the shield when the flange 94 of the capsule strikes the tongues 114.

The sensing unit is so mounted that with the vessel 60 vplaced .upon the grate 61 the capsule 12 will be spaced from both the ange 96 and the tongues 114. Also, the upper portion 96 of the rim 18 of shield 14 will be in engagement with the lcooking vessel, the shield being -vbiased upwardly by means including a spring 120 and which will now be described.

The shield element16 `is of generally truncated conical form and terminates at its lower end in an inwardly extending annular flange 122 provided with a central aperture 124 tting loosely around the upper end of post 22 and adapted to abut against the underside 126 of the reducer coupling element head 86. The shield element 16 is thus slidably mounted relative to the post and it is resiliently biased upwardly by the spring 120. The spring is surrounded by an inverted spring retainer cup 20 having a dependent skirt portion 130 and inwardly extending flange portion 132 abutting against the inwardly extending flange 122 of shield element 16 and terminating in a downwardly extending portion 134 slidably mounted outside of the post. It will be noted that the spring 120 fits around the downwardly extending portion 134 of the flange 132.

The lower end of spring 120 bears against an abutment washer 136 which is generally C-shaped and mounted on the post at a region by opposed tongues 137 thereon extending into openings 138 on the post (see Fig. 4).

lt should be noted that the shield element 16 is also provided with a longitudinally extending slot 140 for assembly purposes as will now be described.

The sensing unit of the present invention may be assembled in relatively easy fashion even though the capillary tube 24, extending between the sensing unit and valve 26, may be of some length. At the present time the assembly Vis substantially as follows: The spring retainer cup 20 is placed around the coupling element 76. The lower capillary tube 24 is inserted into the lower end of the reducer coupling element through the spring retainer cup. The upper capillary tube 88 is inserted into the upper end of the reducer coupling element and both tubes are then brazed to the coupling element. The capsule element 12, which is preassembled, is then brazed to the upper ends of the upper capillary tube 88. The fitting 40 with the thermostatic actuating means is also attached to the capillary tube 24, whereby the iluid system is completed. The fluid system including the capsule 12, two capillaries and the thermostatic actuating Ameans is then filled with thermostatic fluid through the filler tube 102 in known manner.

Thereafter, the lower shield portion 16 is placed in position, it being inserted laterally over the tube 24 and threaded upwardly, the spring cup 20 being slid downwardly onto tube 24 to enable this to be done. The rim 18 can be then inserted into place or the rim can be assembled `in place as a last step in the operation. ln any event, the rim can be slid onto the upper end of shield element 16 by slightly compressing the latter, this being permitted by the lslot 140 in member 16.

Thereafter, the post, base, and washer 136, which are preassembled, and the spring 120 are inserted onto the capillary tube 24 and moved upwardly until the post encircles the coupling element and the tongues 80 spring into the groove 82 thereby to hold the post in assernu bled relation.

After assembly of the sensing unit, it is placed on the range and supported relative to the burner 50 so that the capsule 12 and rim 18 extend slightly above the burner in the absence of a cooking vessel. When a cooking vessel is placed upon the grate, the capsule 12 and rim 18 are engaged and depressed but both remain in engagement with the bottom of the vessel. The capsule thus is in a heat transfer relation with the vessel and the thermostatic fluid therein expands and contracts in'accordance with the temperature of the vessel and these contractions and expansions in volume are transmitted to the thermostatic actuating means of valve 26 thereby to regulate the ow of gas to the burner. The capsule is shielded from the burner by the shield and it is further isolated by the ow of air upwardly around yit in the central opening 52 of the burner. The inverted conical shape of the sensing unit enhances the flow of air around it better to isolate it.l

While the present'iuvention has been shown and described in connection with the details of an embodiment thereof, it should be understood that these details are intended to be illustrative and not limitative of the invention.

Having thus described our invention, what wedesire to secure by United States Letters Patent is as follows:

1. A thermostatic control for burners of the type including a central generally tubular opening, including in combination, means including a thermostatic uid containing capsule and capsule shielding structure of a size to fit into said opening for supporting said capsule in said opening in engagement with the underside of a cooking vessel placed over said burner, said shielding structure including a downwardly and inwardly converging portion adapted to create a greater air flow upwardly around the supporting structure, said supporting means including also a post and a coupling with an enlarged head portion extending laterally beyond the post, the shielding structure having a lower end slidably tting over the post and abuttable against the enlarged head portion, and spring means biasing said shielding structure upwardly.

2. A thermostatic control for burners of the type including a central generally tubular opening, including in combination, means including a thermostatic fluid containing capsule and capsule shielding structure of a size to tit into said opening for supporting said capsule in said opening in engagement with the underside of a cooking vessel placed over said burner, said shielding structure including a downwardly and inwardly converging portion adapted to create a greater air ilow upwardly around the supporting structure, said supporting means including also a post and a coupling with an enlarged head portion extending laterally beyond the post, the shielding structure having a lower end slidably tting over the post and abuttable against the enlarged head portion, spring means biasing said shielding structure upwardly, and a spring cover cup secured in inverted position around the spring and having a portion between the lower end of the shielding structure and spring.

3. A control as claimed in claim 2, wherein the lower end of the spring abuts against a washer mounted upon the post.

4. A thermostatic control for burners, including in combination, a thermostatic iiuid containing capsule, an assembly including lirst and second capillary tube portions and a tubular coupling element secured between and interconnecting said portions, the first of said portions being secured to said capsule, a tubular shield element around said capsule and the first of said portions, and tubular supporting structure supporting said shield element and secured to said coupling element, said shield element and supporting structure -being longitudinally slotted to facilitate assembly thereof relative to said assembly.

5. A thermostatic control for burners including a thermostatic luid containing capsule, a rst capillary tube secured at one end to said capsule, a coupling element secured to the other end of said tube, a second capillary tube having one end secured to said coupling element, a longitudinally slotted supporting post, and means including detachable interengaging elements on said post and coupling element for securing them in assembled relation.

6. A thermostatic control for burners, including in combination, a thermostatic iiuid containing capsule, supporting means for said capsule including a capillary tube and a tubular coupling element secured to said tube, a capsule shield element surrounding said capsule and said tube and slidably secured relative to said coupling element, and a supporting post detachably secured to said coupling element.

7. A thermostatic control for burners, including in combination, a thermostatic uid containing capsule,

-(i supporting means for said capsule including a capillary tube and a tubular coupling element secured to said tube, a4 split supporting. post, and means detachably securing saidpost to said coupling element including a groove on said element and tongues on said post eX- tending into said groove.

8. A thermostatic control for burners, including in combination, a thermostatic uid containing capsule, supporting means for said capsule including a capillary tube and a tubular coupling element secured to said tube, a supporting post detachably secured to said coupling element, and a shield for said tube and capsule mounted and supported upon said post.

9. A thermostatic control for burners, including a thermostatic fluid containing capsule, a first capillary tube secured at one end to said capsule, acoupling element secured to thevother end of said tube, a second capillary tube having one end secured to said coupling element, a split supporting post, means including detachable interengaging elements on said post and'coupling element for securing them in assembled relation, and a capsule shielding element slidably mounted on said post.

10. A thermostatic control for burners, including a thermostatic liuid containing capsule, and shield vstructure for said capsule includinga tubular element having tongues struck inwardly at its upper end extending so as to underlie said capsule and a second element constituting a rim having a tubular portion with tongues engageable with the first element Where said first tongues are struck out and an inwardly extending ange overlying said capsule.

1l. A thermostatic control for the burner of a range, including in combination, a base plate, a tubular post secured to and extending upwardly from said plate, a tubular coupling element mounted at the upper end of said post, a capillary tube secured to the lower end of said element, said element having an upper end portion extending above and seated upon the post and a lower portion extending into said post, said element having an annular groove in the region within the tube and the tube having tongue portions bent into said groove whereby the post and element are held in assembled relation, said post and plate being slotted to enable assembly thereof relative to the coupling element and capillary tube by lateral insertion of the capillary tube into the tube and base through the slots therein, a second capillary tube having an intermediate helical portion to provide a resilient mounting and secured to the upper end of said coupling element, a thermostatic capsule secured to the upper end of said second capillary tube and resiliently supported thereby, an annular slit shield surrounding said second capillary tube, said shield being generally conical in shape and having an inwardly projecting lower end below and abuttable against the underside of the upper end portion of said coupling element and a short upper vertically extending portion with a plurality of tongues bent inwardly below the capsule to limit downward movement of the capsule, a rim mounted at the upper end of said shield, said rim having an inwardly extending flange engageable by the capsule to limit upward movement of the capsule and having also a plurality of tongues engageable in the region of the tongues in the shield whereby the rim is secured to the shield, and means for biasing the shield upwardly including an inverted cup-like element mounted on the post below the shield and adapted to engage the lower end of the shield, a washer secured to the post below the coupling element and a spring on the post abutting against the washer and the upper end of the inverted cup-like element.

12. A thermostatic control for the burner of a range, including in combination, a base plate, a tubular post secured to and extending upwardly from said plate, a tubular coupling element mounted at the upper end of saidpost, said element having an upper end portion eX- tending above and laterally to the side of lthe post, a capillary tube having an intermediate helical portion to provide a resilient mounting and secured to the upper end of said coupling element, a thermostatic capsule secured to the upper end of said capillary tube, an annular shield surrounding Isaid capillary tube, said shield having an inwardly projecting lower end below and abuttable against the underside of the upper end portion of said coupling element and having also an upper end portion with a plurality of tongues bent inwardly below the capsule to limit downward movement of the capsule, a rim mounted at the upper end of said shield, said rim having an inwardly extending flange engageable by the capsule to limit upward movement of the capsule and having also a plurality of tongues engageable in the region of the tongues in the shield whereby the rim is lsecured to the shield, and means for biasing the shield upwardly including a washer secured to the post below the coupling element and a spring on the post abutting against the washer and acting against the lower end of said shield.

13. A thermostatic control for yburners of the type including a central generally tubular opening, including vin combination, means including a thermostatic iluid size to fit into said opening for supporting said capsule in said opening in engagement with the underside of a cooking vessel placed over said burner, said shielding structure including a downwardly and inwardly converging portion adapted to create a greater air ow upwardly around the supporting structure, said supporting means including also a post and a coupling with an enlarged head portion extending laterally beyond the post, and the shielding structure having `a lower end slidably tting over the post and movable toward the enlarged head portion.

14. A thermostatic control for a burner, including in combination, a thermostatic fluid containing capsule, supporting means for said capsule including a capillary tube and a tubular -coupling element secured to said tube, a tubular supporting post for said coupling element, and a shield for said tube and capsule slidably mounted upon said post.

References Cited in the le of this patent UNITED STATES PATENTS 947,914 Junkers Feb. 1, 1910 2,303,012 Weber Nov. 24, 1942 2,456,864 Cole Dec. 21, 1948 Turner Ian. 11, 1955 

